Jump to content

solar brackets


kingswood

Featured Posts

If you were on a boat last Saturday you would realise that you need to screw things in. Sikaflex would not have held large panels down in that wind.

Drill and tap, 5.5 bit and M6 tap, fit security bolts, (hex top or similar) . Use sikaflex to seal the bolts in.

Link to comment
Share on other sites

24 minutes ago, kingswood said:

do i need to screw and glue tilting solar brackets onto roof or can i just sikaflex them on not keen on drilling holes

My 2 x 150 watt panels are held down with 4 non tilting feet of less than 2 sq in each adhered to the roof with Stixall from Toolstation.  No holes to leak, no rust and the adhesive manufacturer claims it to be able to be used to bond items under water, so no issue with exposure to rain once cured on the NB roof. I chose it after recommendations on this forum.  The panels happily endured the "apocalyptic" storms we had recently and the feet are as secure as ever.

Link to comment
Share on other sites

Bear in mind that any adhesive can only be as strong as the substrate to which it adheres. If the roof is painted then it’s irrelevant how good the adhesive is, it’s the paint bond that’s going to be holding the panel on. 

Link to comment
Share on other sites

1 hour ago, Sea Dog said:

My 2 x 150 watt panels are held down with 4 non tilting feet of less than 2 sq in each adhered to the roof with Stixall from Toolstation.  No holes to leak, no rust and the adhesive manufacturer claims it to be able to be used to bond items under water, so no issue with exposure to rain once cured on the NB roof. I chose it after recommendations on this forum.  The panels happily endured the "apocalyptic" storms we had recently and the feet are as secure as ever.

.....but are your feet at each corner? If so I can see why it works. For tilting mounts, they are generally in the center of the end of the panels so there will be a lot more leverage for the wind to act on. Tony's right about the paint. Screw 'em down.

Link to comment
Share on other sites

4 hours ago, kingswood said:

do i need to screw and glue tilting solar brackets onto roof or can i just sikaflex them on not keen on drilling holes

 

Yes you can but the more panels you lose, the keener you'll get on drilling and tapping holes.

 

 

 

 

 

  • Haha 3
Link to comment
Share on other sites

9 hours ago, Dr Bob said:

.....but are your feet at each corner? If so I can see why it works. For tilting mounts, they are generally in the center of the end of the panels so there will be a lot more leverage for the wind to act on. Tony's right about the paint. Screw 'em down.

This is indeed true Dr Bob and the OP was referring to tilting panels, though whether the increased contact patch would be sufficient for the mighty Stixall to then be 100% reliable I don't know. However, I chose my mounts for the avoidance of roof holes, which I see as something to avoid generally. The other reasons were lower profile, neater appearance, lesser snagging hazard for the centre line and cost. I consider these outweigh the benefits of tilting panels, which I think are exaggerated anyway, particularly for non-static boats.

Link to comment
Share on other sites

4 hours ago, Sea Dog said:

This is indeed true Dr Bob and the OP was referring to tilting panels, though whether the increased contact patch would be sufficient for the mighty Stixall to then be 100% reliable I don't know. However, I chose my mounts for the avoidance of roof holes, which I see as something to avoid generally. The other reasons were lower profile, neater appearance, lesser snagging hazard for the centre line and cost. I consider these outweigh the benefits of tilting panels, which I think are exaggerated anyway, particularly for non-static boats.

....and the number of trees that hang over many nice mooring spots.

Link to comment
Share on other sites

I used silicon to stick my mounts - two panels have z brackets so are very close to the roof, less chance for the wind to get a good hold. The other two panels I wanted to be able to tilt, so I used regular brackets, bolted to the ends of the panels and stuck to the roof with silicon (I can take two bolts out on the side I want to lift, and keep the panel with stays). These panels are also just as low to the roof when down.

Silicon bonds very well and as long as you have it as a very thin layer it is strong.

Link to comment
Share on other sites

1 hour ago, Johny London said:

I used silicon to stick my mounts - two panels have z brackets so are very close to the roof, less chance for the wind to get a good hold. The other two panels I wanted to be able to tilt, so I used regular brackets, bolted to the ends of the panels and stuck to the roof with silicon (I can take two bolts out on the side I want to lift, and keep the panel with stays). These panels are also just as low to the roof when down.

Silicon bonds very well and as long as you have it as a very thin layer it is strong.

In my days managing a speciality paints group, we also did high performance adhesives. The mode of failure is a 'pull' mode where the force from the wind is applied at right angles to the roof. This is therefore a good application for adhesives IF a big enough surface area is stuck to the roof. I've not done the calcs.....and forgotten how to do them......(I always got a little man to do them for me....) but I doubt if the current typical tilting mounts are anywhere near big enough in a 50mph gale. The real problem as Tony said earlier, in most cases you are not sticking them to the roof. You are sticking them to the paint on the roof which will not bond as well as the Sikaflexwotever. I got a little man in to bolt my panel mounts on (with sikaflexwotsit) as I couldnt bear the thought of drilling holes in my roof. If you are just using adhesive, then scrape back to bare steel first.

Link to comment
Share on other sites

1 hour ago, Johny London said:

I used silicon to stick my mounts - two panels have z brackets so are very close to the roof, less chance for the wind to get a good hold

It's the wind flowing over the top that will dislodge them. Google the Bernoulli Effect and meditate on how wings provide lift for flight ............

Link to comment
Share on other sites

6 minutes ago, Up-Side-Down said:

It's the wind flowing over the top that will dislodge them. Google the Bernoulli Effect and meditate on how wings provide lift for flight ............

.....and make sure you have enough bricks in the bilge otherwise you will take off.

.

.

.

.

.

eta, doesnt a wing need a longer path over the top compared to the bottom to give lift? If the bottom had a longer path, then it would give you additional downforce .....which would be useful for all the bends on the South Oxford........or not 'as the bends are shallow. Maybe an upside down spoiler on the back of the boat would be useful on the south oxford?

Edited by Dr Bob
Link to comment
Share on other sites

Then the benloiu effect will help the panels stay down as the roof is curved so that's the longer surface.

Anyway, the first pair have been on for a couple of years now with no problems, and believe me they've seen some pretty severe gales. Every so often I give them a tug to check, but still 100% firm - but I have good paint on the roof (not oil based).

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.